I am having trouble getting my car emission tested.
At two different places, the emissions test equipment could not establish a communications link with my car.
Last night I used VAG-COM release 303.1 and it passed the OBD-II function test but Alex Peper's Vehicle Explorer Scan Tool rev 1.05 could not communicate with my ECU.
Any clues??

And you can read stuff from the ECU, then there must be a setting in that Vehicle Explorer Scan Tool that is misconfigured (serial port settings are the problem 9 out of 10 times)

However, it may not even work - I've never tried hooking up non-VAG tools to my car. Sorry I couldn't be more help... maybe someone else could verify this for me (us) ?

Yes I do.
That was the first thing I suspected. I removed the radio only to find out that the K-line going into the aftermarket radio wire harness was a no connect on the other end.
Strange thing is that VAG-COM works perfectly. I am able to get a reply back from all of my controllers when doing the system scan and the OBD-II function test reports no issues.

Even though I hated doing it, I brought the car to the local Audi dealership as a last resort.
Amazingly the car passed the emissions test without any of the communication problems that I experiance at the previous two testing stations.
Now I can have some fun by digging into VAG-COM and learning everything about this cool tool!